Known heald shaft rods in looms have a connection end formed into a fork with two fork legs. Each of the two fork legs has an open, conical stamped countersunk recess and these recesses are positioned axially opposite each other. An inner ring of a roller bearing is held in place between the fork legs and the two conical stamped recesses. The recesses are intended to center the inner ring of the roller bearing. It is known to clamp the roller bearing inner ring between the forked legs of the heald shaft rod by a countersunk threaded nut and a countersunk screw, whereby the countersunk nut is loosely received in the stamped recess.
When the bolt and nut are to be interconnected in such a conventional screw connection, there is a tendency that one of the connecting members, either the nut or the screw, turn with the turning of the other member of the connection. This turning is a disadvantage because it makes it rather difficult to assemble or disassemble the heald shaft rods or linkage of a loom equipped with such screw connections.
Furthermore, a certain safety must be provided, for example, against an unintended loosening of the screw and nut connection after the connection has been installed. In order to solve the safety problem it is known to employ a high strength adhesive bonding between the female threading of the nut and the male threading of the screw. However, this solution only solves half of the problem because when the screw connection must be disassembled, for example in order to replace the roller bearing or for any other maintenance reason, it is difficult to achieve the separation of the nut from the screw because the adhesive bonding essentially provides a non-releasable connection so that without special tools the connection cannot be released. Such special tools, for example, involve the use of hot air or a gas flame providing a temperature sufficient to soften the adhesive of the bond. It has been found that such application of heat generally destroys the roller bearing and also diminishes the material strength of the heald shaft rods or links at least in the area where they have been heated.
It is known from French Patent Publication 2,621,362 (Corain et al.), published on Apr. 7, 1989 to connect the fork leg with the bearing carrying rod end with a nut having a female threading cooperating with a male threaded screw and a Belleville washer which when tightened provides an axial force component that is intended to prevent the loosening of the connection in operation.
U.S. Pat. No. 5,244,326 (Henriksen), issued on Sep. 14, 1993, describes a nut and bolt connection for containers, portable housing, and the like, wherein the nut or female screw part is provided with external serrations that are biting into the container walls which are to be interconnected when the nut is hammered in the material of the wall. Once the serrations are in place, they are permanently anchored in the wall material and repeated removal and reinsertion are not intended.